Method and means for closing tubes by spinning



6, 1958 E. E. GRAVES ETAL 2,848,804

METHOD AND MEANS FOR CLOSING TUBES BY SPINNING Filed Oct. 18, 1945 NETHOD AND MEANS FOR CLOSING TUBES BY SPINNDJG Edwin E. Graves and Robert H. Coonfare, Columbus, Ohio, assignors to the United States of America as represented by the United States Atomic Energy Commission Application October 18, 1945, Serial No. 623,128

6 Claims. (Cl. 29--543) The present invention relates generally to metal-working methods and tools, and more particularly to an improved spinning and cutting tool for and a method of producing a fold-free closed end on an aluminum jacketing tube.

Aluminum, because of its excellent corrosion resistance and other properties, is an example of a good material with which to sheath or jacket bodies for the purpose described. 1

In order to prevent leakage or other failure through these aluminum jackets, they must be formed of uniform thickness and with as few seams as possible so as to reduce the possibility of galvanic corrosion. Jackets are preferably welded to complete the closure so as to obtain as near a continuous homogeneous sheath as possible. ltfollows that the welded sealing area should be kept as small as is practicable.

One of the principal objects of this invention isto provide a novel method for spinning the closure of such jackets. There is also provided a novel tool of the type described having a spinning or flattening surface that may be fed across the spherically spun open end of an aluminum sheathing tube whereby the aluminum flows into a plane surface over the end of an enclosed metal body at right angles to the tube; a first cutting edge that removes by successive layers the excess aluminum contained in folds formed in the aluminum by the spinning surface; and a. final cutting edge that finishes the aluminum end surface to a predetermined thickness.

The foregoing, as well as other objects, will be made more apparent from the description of an embodiment of the invention, especially when considered in connection with the accompanying drawings, wherein:

Fig. 1 is a perspective view of a tool constructed in accordance with the teachings of the present invention;

Fig. 2 is a fragmentary longitudinal cross-sectional view of an open-ended jacketing tube on a metal body and a spinning tool for forming a hemispherical end thereon;

Fig. 3 is a plan view ofthe tool of Fig. 1 shown with respect to the hemispherical preformed end of the jacketing tube of Fig. 2, the tube and its enclosed metal body being in section;

Fig. 4 is a side elevational view of the tool taken along line 4lof Fig. 3;

Fig. 5 is a side elevational view at 180 to the view of Fig. 4 of the tool and jacketing tube showing the position and direction of movement of the tool relative to the tube; and

Fig. 6 is a fragmentary longitudinal cross-sectional view similar to Fig. 2, of the finished workpiece.

Referring more particularly to the drawings, the tool 1 generally comprises a substantially straight steel shank 2 having a spinning surface inclined at an angle with respect to the left side surface or working edge 3 of the shank 2; a first cutting edge 6 for trimming excess metal from the end of a workpiece 8; and a second cutting edge Iii) for finishing the Worked surface or the workpiece.

"ice

More particularly, the spinning surface 4 is spherically formed and has a radius of approximately 2 /2 inches with the center of generation located so that the surface 4 forms with the left side 3 a curved edge 12 of 2% inches radius. The edge 12 is provided with a /3 of an inch bevel to permit ready flow of metal thereover. The upper portion of the surface 4 intersects with a cylindrical cut-away surface 18 to form the first cutting surface 6. Surface 18 has a radius of generation of approximately 2% inches, and the axis of generation is located so that the surface 18 forms with the top surface 20 of the shank an upper edge 21 disposed at an angle of 107 and 10 minutes to the right hand side 22 of the shank. As illustrated in Fig. 1, the edges 12 and 6 intersect at a point approximately of an inch below the top surface 2d so that the short cutting edge 10 is formed by the left side surface 3 and the under-cut surface 18. The embodiment of the tool 1 as thus far described has a length of approximately 1 inches from point 24 to the tip 26. The edge 12 extends forward a distance of approximately of an inch to a point approximately /3 of an inch from the tip of the tool 1. While the tool 1 which has been described may be modified to perform operations on various types of workpieces, the tool specifically described is particularly adapted to finishing the end of a tubular piece of stock in a manner hereinafter described.

Referring to Figs. 2 and 3, there is illustrated a workpiece 8 comprising a cylindrical aluminum tubular member 30 tightly fitted to a corrodible body 32 having a right-end 34. The tubular aluminum member extends outwardly from the end 34- a distance slightly less than its radius. The protruding portion is preformed to a substantially hemispherical contour of a smaller radius of curvature than that of the spinning surface 4 by a suitable rotating die 36 to produce the hemispherical end 38 thereon, as illustrated in Figs. 3 and 5. Thereafter, the end 38 is fashioned by the afore described tool 1 to closely overlie the end 34 of the body 32 by exerting a reducing pressure on the end 38 as the latter and the tool are relatively rotated and moved in directions toward each other. The forming surface 4 of the tool 1 exerts a reducing pressure successively around the entire circumferential surface of the hemispherical end 38 to progressively heat the latter to a plastic or easily workable condition, and thereafter to continually flow the aluminum to the position 39 illustrated in Fig. 6.

As folds or wrinkles occur, the cutting edge 6 successively removes the existing material beginning at a point P and proceeding along the cutting edge 6 to a point P (Fig. 3). Thus the point of contact between the spinning surface 4- and the workpiece moves radially outwardly from the axis of the workpiece, although the motion of the tool 1 is a simple cross-feed toward the axis of the workpiece. Thereafter, the aluminum is forced by the tool surface 3 into tight engagement with the right-end 34 of the enclosed body 32, and any excess aluminum remaining is trimmed to a predetermined uniform distance from end 34 by the second cutting edge 10 lying in the plane of the final spinning surface 3. Thereafter, the small opening remaining in the fiat end-surface 39 may be aluminum spot welded as at 40 to completely seal the jacket with a minimum of Welding area.

One of the primary features in the design of the tool 1 and in the method described is that the forming pressure is exerted at different points on the tool during the forming cycle thereby minimizing wear and galling.

It will be noted that the tool 1 illustrated is designed for linear movement into operative contact with the rotating workpiece 8 along its own linear axis and at right-angles to the axis of rotation of the workpiece so that the edge 3 is approximately perpendicular to said axis as shown in Fig. 3. Likewise, the second cutting edge 119 lies in and travels along a line through the axis the tool relative-to the workpiece while, at the same time, maintaining the-sequenceof forming and successive cutting and trimming operations in a single pass of the tool.

It is to be understood that the workpiece 8 is suitably supported for rotation about its longitudinal axis, and that the tool 1 is suitably supported for linear movement as set forth. Any well known supports capable of imparting the required movements and disposing the workpiece 8 and tool 1 as described will suffice.

Other variations of and applications for the present invention will be apparent to those skilled in the art, and the invention, therefore, is to be limited only by the scope of the appended claims.

We claim: M

1. In a spinning tool, the combination of a substantially straight shank adapted for longitudinal movement radially of-a rotating work piece, a working edgelying in a plane perpendicular to the axis of rotation of the work, and a spinning surface terminating in said working edge, at least a portion of said spinning surface being inclined at an acute angle with respect to said axis, whereby the area of contact between the rotating work and the tool will move along said spinning surface as the tool is moved radially with respect to the work, and a cut-off surface inclined to said spinning surface so that the effective spinning surface area between said working edge and said cut-off surface decreases toward the portion of 'said spinning surface that contacts the work near the axis of rotation.

2. The method of closing the end of a hollow cylindrical body which comprises forming the end substantially to the shape of a hemisphere, rotating the cylindrical body about its axis and progressively positioning a non-rotating tool with a tapering spherical spinning surface of larger radius of curvature than said hemispheric end toward the axis of rotation so that the area of tool contact with the rotating body moves along the tool surface toward the tapered portion thereof and radially outwardly from the axis of the body as the tool approaches the axis.

2,848,804, r g A 3. In a spinning tool, a shank with a concave arcuate spinning surface and a second concave arcuate surface intersecting said spinning surface to define therewith an arcuate cutting edge at one'margin of said spinning surface, and a substantially flat spinning surface intersecting said second surface to define another cutting edge merging with the first-mentioned edge, said first arcuate surface tapering toward said other cutting edge. a

4. The method of spinning the end of a hollow cylindrical body comprising forming said .end substantially to the shape of a hemisphere, rotating the same about its axis while progressively positioning a spinning surface in the form of a tapered segment of a sphere having a radius of curvature larger than that of said hemispheric end 'rectilinearly toward said axis to progressively move the area of contact between said body :and said surface toward the smallest portion of said segment, away from 5. A spinning tool comprising an elongated shank having two arcuately concave surfaces at the end thereof and a plane surface forming a side thereof, said three surfaces intersecting at a point on the end to form at said end a first cutting edge defined by the line of intersection between said arcuate surfaces and a second cutting edge defined by the line of intersection between one of said arcuatesurfaces and the plane surface, said second cutting edge being continuous with the end of the first cutting edge.

6. A spinning tool comprising an elongated shank having at an end thereof an arcuately concave surface tapered to a point, a first cutting edge defined by one edge of the surface and terminating in the point, and a second cutting edge extending away from the tapered surface transversely of the shank and continuous with the first cutting edge at the point.

References Cited in the file of this patent UNITED STATES PATENTS I 389,761 Phillips Sept. 18, 1888 501,547 Thomson July 18, 1893 675,184 Armstrong May 28, 1901 1,267,782 McKerahan May 28, 1918 1,361,851 Hall Dec. 14,1920 2,173,759 McCloskey Sept. 19, 1939 2,284,210 Johnson May 26, 1942 

